Signaling system for railroads



. Sept. 22, 1931. w. K HOWE 1,324,147

SIGNALING SYSTEM FOR RAILROADS Filed July 25, 1929 T0 816 NAL ATTORNEY Patented Sept. 22, 1931 arrsn STATES PATENT OFFICE I WINTHROP K. HOWE, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK SIGNALING SYSTEM FOR RAILROADS Application filed. July 23, 1929. Serial No. 380,286.

This invention relates to interlocking systems for railroads, and more particularly pertains to the control of devices for indicat* ing the position of track switch points.

In interlocking systems, it is necessary to govern the indications of'signals in accordance with the positions of the points of switches over which the signals govern traiiic; and it is often desirable or expedient to provide a relay in the tower which indicates the position of the points of the associated switch, It has been proposed to control such a relay, sometimes called a SS relay, through the medium-of a polarized circuit, energized by either alternating current or direct current over a separate pair of line wires extending from the switch to the relay in the tower.

One object of the present invention is to control such an SS relay in the tower in accordance with the position and locked condition of the switch points of a distant power operated track switch over the regular control wires used for supplying power to said switch, so as to avoid the need of additional wires between the switch and the tower for the purpose of controlling the SS relay. More specifically, it is proposed, in accordance with the present invention, to superimpose alternating current on the control or opcrating wires used for the operation of a direct current switch machine, and utilize this alternating current to actuate a two element three-position relay to a position in accord ance with the position and locked condition oi the switch points by which it is controlled.

Further objects, purposes and characteristic features will be in part obvious and part pointed out as a description of the accompanying drawing progresses.

In describing the invention in detail, reference will be made to the accompanying drawing, in which the single figure shows diagrammatically the present invention as appliedto one type of interlocking control for a single power operated switch machine.

Referring to the drawing, a track switch TS is shown as operated by a switch machine SM in the usual manner. This switch machine SM is governed by a lever L in the interlocking tower in any suitable manner, one such system being completely described in my Patent No. 1,550,611, dated August 18, 1925. However, in order to simplify the description of the present invention, only the mechanisms directly coacting with the present invention have been shown. 8

The switch machine SM may be any suitable power operated switch machine, such by the way of example as shown in my Patent 1,466,903, dated September l, 1923, having the usual 1notor,with an armature A and field winding F, and provided with two groups of contacts known as pole changing contacts PC, and point detector contacts PD. The pole changing contacts PC include movable contact blocks 5 and 6 which make contact. between two pairs or" fixed contacts with the switch machine SM in the present normal position, as shown, and are operated to an opposite extreme or reverse position with the switch machine SM over and locked in the reverse position, thereby making contact between certain other two pairs of fixed contacts. These pole changing contacts PC make possible the operation of the switch machine in opposite directions by connecting the motor to the-next operating control wire.

The point detector contacts PD include movable contact blocks 7 and 8, which make contact between two pairs of fixed contacts in the normal position, as shown, and make contact between two other pairs of fixed contacts when in an opposite extreme or reverse position. The movable contact blocks 7 and 8 are operated to extreme positions when the switch machine SM and track switch TS are both operated to and are locked in corresponding extreme positions, and they assume a central, or non-contacting position during the operation of the switch machine SM and also at any time that the switch points of the track switch TS are not in extreme positions. An example of such point detector contacts is shown and described in the patent to C. S. Bushnell, No. 1,507,236 dated November 25, 1924.

In the tower, a lever L. is provided for controlling the movable cont-act blocks 9 and 10 which make contact between certain fixed ill pairs of contacts when in the normal or in the reverse positions. Associated with the lever L is the usual indication latch mechanism 11, indication magnet 12 and safety magnet 13, which cooperate with the lever L, as completely explained in my above mentioned Patent No. 1,550,611. A polarized relay P is provided to furnish cross protection in the usual manner.

. An indication selector IS is provided, having normal and reverse operating coils 14 and'15, which are included in the normal and reverse operating circuits respectively. These coils 14 and 15 control the dead beat armature 16 to extreme positions for selecting the next dynamic indication circuit.

A suitable power supply for operating the switch machine SM and controlled by the lever L is furnished by a battery 17, or other suitable direct current source.

Also, an SS relay is provided in the tower, having a local phase winding 18 and a line phase winding 19, which operates a contact 20 to either of two extreme positions, depending upon the relative" instantaneous polarities within the local phase winding 18 and the line phase winding 19, with the con tact 20 assuming a neutral position when either or both of the two-phase windings are deenergized. The local phase winding 18 of the relay SS is continuously energized from the secondary of a transformer T which is local to the interlocking tower, the primary of which is energized from a suitable single phase alternating current source. The line phase winding 19 of the relay SS is connected in series with a condenser C across the normal and reverse operating wires N and R,

which connect the lever L with the switch,

machine SM.

The point detector contacts PD of the switch machine SM are connected for changing the instantaneous polarity of the alternating current supplied to the normal and reverse operating wires N and B when the movable contact blocks 7 and 8 are in certain extreme positions. This current is supplied from the secondary of a transformer T with a condenser C connected in series. The primary of the transformer T is provided with suitable alternating current potential from the same source which supplies the transformer T in the interlocking tower over two line wires interconnecting the tower with the switch.

The contact 20 of the relay SS is shown as connecting a suitable source of positive potential (B+) to certain signal control circuits when in extreme energized positions, and energizing an indicator lamp 21 when in a deener-gized position. These signal circuits selected or controlled by the SS relay are not shown, as they may be any suitable signal circuits for controlling signals governing the route over the track switch TS and are well known to those skilled in the art.

Operation:As heretofore stated, the local winding 18 of the relay SS is continuously energized by the secondary of transformer T thus, with the point detector contacts PD in the present normal position, due to the switch machine SM and the track switch TS being in a normal locked condition, the line phase winding 19 of the relay SS is energized over a circuit traced as follows :from the right hand terminal of the secondary of transformer T through condenser C wires 25 and 26, fixed contact 27, movable contact block 8, fixed contact 28, wires 29 and 30, reverse operating wire R, Wire 31, condenser C line phase winding 19 of relay SS, wire 32, normal operating Wire N, wire 33, fixed contact 34, movable contact block 7, fixed contact 35, wires 36 and 37, to the left-hand terminal of transformer T Although there are two direct current circuits in multiple with the line phase Winding 19 of the SS relay, the alternating current potential drop across the line phase winding 19 of the relay SS is maintained by the high alternating current impedance of the direct current COllS l4 and 15 of the indication selector 1S, the coils of the indication magnet 12, the winding of the polarized relay P, and the coils of the safety magnet 13. One circuit in multiple with the line phase winding 19 is traced as follows :from the right-hand terminal of line phase winding 19 of relay SS, through wires 32 and 3,8, fixed contact 39, movable contact member 10, fixed contact 40,

Wire 41, coil 14 of indication selector IS, Wires l 42 and 43, windings of safety magnet 13, wire 44, battery 17, wire 45. contact'46, wire 47, winding of relay P, wire 48, windings of indication magnet 12, wire 49, contact 16 of indication selector IS in a normal full line position, wire 50, fixed contact 51, movable contact member 9, fixed contact 52, wires 53 and 31, condenser C to the left hand terminal of line phase winding 19.

Another circuit including the armature A and field winding F of the motor is also in multiple with theline phase winding 19 of the relay SS, but as this circuit alio includes direct current apparatus of high alternating current impedance the voltage drop across the line phase winding 19 is not appreciably affected. This second multiple circuit across the line phase winding 19 of the relay SS is traced as follows :from the right-hand terminal of the line phase winding 19, through wires 32 and 38, fixed contact 39, movable contact member 10, fixed contact 40, wire 41, winding 14 of indication selector IS, wires 42 and 43, windings of safety magnet 13, wire 44, battery 17, wire 45, contact 46, common return wire C of switch machine SM, field winding F, wires 60 and 61, fixed contact 62, movable contact block 5, fixed contact 63, wire 64, armature A, wires 65 and "66, fixed contact 67, movable contact block 6, fixed contact 68, Wires 69 and 30, reverse operating wire R, wire 31, condenser C to a left-hand terminal of the line phase winding 19 of the relay SS.

lVhen lever L is moved to its reverse positions, so that the movable contact members 9 and 10 complete circuits through certain reverse pairs of fixed contacts 71 and 72-73 respectively, the switch machine SM receives operating current over the reverse operating wire R to cause operation of the switch machine SM in the usual well-known manner.

During the time that the switch machine SM is in an unlocked operating condition the movable contact blocks 7 and 8 of the point detector contacts PD assume acentral position, resulting in the de-energization of the line phase winding 19 of the relay SS. With the contact 20 of the relay SS in a deenergized position the indicator lamp 21 is supplied with current from a suitable positive source of potential (13+ through contact 20, wire 54, through indicator lamp 21 to the opposite terminal (B) of the suitable source. The illumination of the indicator lamp 21 indicates that the switch'machine SM has ini tiated its operation.

It is obvious from the drawing that the current supplied by the battery 17 must flow through the safety magnet 13 and through either the coil 14 or the coil 15 of the indication selector IS in accordance with the position of the control lever L. Thus, with the movable contact member 10 in a reverse position the control current of the switch machine SM must flow through the coil 15 of the indication selector IS, which results in the movement of the contact 16 to the reverse dotted line position.

As soon as the switch machine SM has operated the track switch TS to a reverse locked position, the movable contact blocks 5 and 6 of the pole changing contacts PC are moved to reverse positions, at which time a circuit is completed,'due to the energization of coil 15 of indication selector IS and movement of contact blocks 5 and 6 to reverse positions, for energizing the indication magnet 12 and also snubbing the motor armature A by the generation of dynamic current in the usual well-known manner.

Also. with the track switch TS and switch machine SM in reverse locked positions, the movable contact blocks 7 and 8 of the point detector contacts PD are moved from the central or intermediate position to an extreme opposite or reverse position, at which time a reverse energizing circuit for the line phase winding 19 of the relay SS is completed, so as to energize the line phase winding 19 with alternating current having opposite instantaneous polarity in respect to the instantaneous polarity applied to the winding 19 when the normal energizing circuit is completed This reverse energizing circuit for the line phase winding -19 is traced as follows :from the right-hand terminal of the secondary of transformer T through condenser C wire 25, fixed contact 74, movable contact block 7, fixed contact 75, wires 78 and 79, normal operating wire N, wire 32, line phase winding 19 of relay SS, condenser C wire 31, reverse operating wire R, wire 80, fixed contact 81, movable contact block 8, fixed contact 82, wire 37, tothe left-hand terminal ofthe secondary of transformer T The local phase winding 18 and the line phase winding 19 of the relay SS are now en- 1 ergized in a manner to operate the contact 20 to a. left-hand dotted line position resulting in the selecting of certain signal circuits and the de-energization of the indicator lamp 21.

vVi ith the de-energization of the indicaton lamp 21, the operator is informed that the switch machine SM has completed the operation of the track switch to a reverse locked position.

During the time that the reverse energizing circuit for the line phase winding 19 is completed, there are two direct current circuits in multiple with the line phase winding 19 which are similar to those two multiple circuits across the line phase winding 19 when its normal energizing circuit is completed as heretofore traced. These circuits will not be traced in detail, as they may be traced by analogy to the normal multiple circuits, and do not effect the operation of the SS relay in as much as the same alternating current impedance heretofore mentioned maintains the voltage drop across the line phase winding 19.

If a cross or short circuit should occur between the normal and reverse operating wires N and B respectively, the energizing circuit of the line phase winding 19 would be shunted so as to de-energize the relay SS. Thus, an additional protection is afforded in combination with the usual cross protection supplied by the polarized relay P, with such a condition immediately made known to the operator by the illumination of the indicator lamp 21.

The switch machine SM may be returned to its normal position by the returning of le'ver L to its right-hand positions, so that the movable contact members 9 and 10 make connection between the contacts 5152 and contacts 394O respectively in a manner well known to those skilled in the art. This normal operation results in the control of the contact 20 first to a neutral de-energized position and then to a right-hand full line normal position as shown.

Thus, the control of a SS relay has been shown as accomplished over the regular control wires of a direct current power operated switch machine by the use of superimposed alternating current. It has also been shown, the manner in which this relay indi cates the position of the track switch with which it is associated thereby facilitating the control of certain signal circuits, or the like.

One specific arrangement of devices and circuits for controlling a switch position indicating relay has been shown and described, as an embodiment of the present invention, however, it is to be understood that the varions devices and circuit arrangements are selected to facilitate the disclosure of the nature of the invention rather than its specific form, as it is obvious that various modifications and adaptations may be made to the present invention without departing from the spirit or scope of the invention as set forth in the following claims.

Having described my invention, I now claim 1. In an interlocking system for railroads, a control lever in an interlocking tower, a distant switch machine, three control wires connecting said control lever with said distant switch machine, an alternating current relay in said interlocking tower operable to any of three positions, and means, including two of said control wires operableto control said alternating current relay to any one of its three positions.

2. In an interlocking system for railroads, a distant switch machine associated with a track switch, a control lever in an interlocking tower, two control wires and a common wire connecting said distant switch machine with said control lever, an alternating current relay in said interlocking tower operable to any one of three positions, and means, including said two control wires, operable to control said alternating current relay to one of its three positions in correspondence with the position assumed by said track switch.

3. In an interlocking system for railroads, a control lever, a distant switch machine controlling a track switch, two control wires and a commonwire connecting said distant switch machine with said control lever, an alternating current relay capable of assuming any one of three positions located at the lever end of said two control wires, means including said two switch machine control wires operable to control said alternating current relay to a neutral position during operation of said distant switch machine, and operable to control said alternating current relay to a particular extreme position at the end of each complete operation of said distant switch machine in correspondence with said track switch.

4. In an interlocking system for railroads, a control lever, a distant switch machine controlling a track switch, two control wires and a common return wire connecting said control lever and said distant switch machine,

an alternating current relay operable to either of three positions, alternating current relay control means operable to control said alternating current relay to one of its three positions in correspondence with a certain position assumed by said track switch including, said two control wires and excluding the common return wire, an alternating current source at said switch machine, pole changing contacts for applying said alternating current to said two control Wires, and means preventing control current for said distant switch machine to affect operation of said alternating current relay control means.

5. In an interlocking system for railroads, a distant switch machine controlling a track switch, a control lever, a normal wire, a reverse wire, and a common return wire con necting said distant switch machine with said control lever, an alternating current relay located at the control lever end of said Wires and operable to either of three positions, means operable to control said alternating current relay to one of its three positions in correspondence with a particular position assumed by said track switch, with said means including a condenser in series with said alternating current relay and said normal and reverse wires, and alternating current source of potential at said distant switch machine, a condenser in series with said alternating current source, pole changing contacts operated by said switch machine to connect said alternating current source and said condenser in series with one instantaneous polarity to said normal and reverse wires when said switch machine assumes one of two extreme positions, to connect said alternating current source and said condenser in series with the opposite instantaneous polarity to said two wires when said switch machine assumes the otherone of two extreme posit-ions, and to maintain the alternating current source disconnected when said switch machine is in any other positions.

6. In an interlocking system for railroads, a distant track switch operated by a switch machine, a control lever, a normal and a reverse control wire, and a common return wire connecting said switch machine with said control lever, an alternating current source, contact means operated to any one of three positions by said track switch and said switch machine mutually coacting for connecting said alternating current source across the normal and reversecontrol wires when in either of two positions, means effective to prevent direct current aii'ecting said alternating current source, and means effective to prevent alternating current afi'ecting said switch machine.

In testimony whereof I aflix my signature.

IVINTHROP K. HOIVE. 

